Expansion boring tool



Jul 1, 1930. c. c. KOELN 1,768,962

EXPANSION BORING TOOL v Filed Feb. 23, 1924 Fjiql.

Ore/577m 6 M51. '/Y.

Patented July 1, 1930 UNI-TED sma- P E m E] 1 Y o RrsrIArr o. ROE-LN, vor s1. Louis, MISSOURI, ASSIGNOR, BY mnsnn Asst-summits,

TO DAVIS MISSOURI BOBING TOOL -.COMPA1\TY OIEST. LOUIS, MISSOURI, A G0 RIEO'RACLION EXPANSION BORING TOOL Application filed Eebruary 23, 1924; Serial No. 694,700.

' V This invention relates to boring tools and more particularly to such tools of the "expansion type. a

One of the objects of this invention is to provide a boring tool of improved construction in which the expanding cutters or blades may be positively adjusted for expansion and accurately set at the required adjust ment.

Another object of this invention is to provide an improved boring tool, which may be economical to ,manufacture, simple to operate, and rugged and durable in service.

Further objects Will appear from the detail description taken in connection with the accompanying drawing, in which 2 Figure 1 is a plan view of the head of a boring tool embodying this invention;

Figure 2 is a section on line 2 2,Fig urel;

Figure 3 is a detail showing the method of securing the cutters;

Figure 4 is "a View similar to Figure 1 showing another embodiment of this invention; f g p t Figure 5 is a perspective detail view of the adjusting Wedge, shown in Figure l; and

Figure '6 is a detail of the clamping devicev of Figure 4.

be of any well known construction; The head '2 of thisbar is'pierced by a transverse opening ,8 which is ioblongin general crosssection' having rounded ends as shown in dotted lines in Figureil ,andtvhich extends "an oblong contour to correspond with that of the restofthe opening. At the center of the opening 3 on this same side, the size thereof is further reduced so as to provide a circular shoulder 5. a From the shoulder 5' the opening is circular and extends is enlarged to form a third shoulder 6, the

Referring nowto the accompanying drawa ing, 1 designates the boring bar which may moves during adjustment.

enlargement having an oblong outline to correspond with the perforation 3.

' The'perforation 3 is adapted to provide'a guide for an adjustingelement 7, the headj8 of which has an oblong contour adapted to fit the perforation 3 for sliding -IlIOVBIi1 GH Cx therein and adapted at the extremity of its upward travel, Figure 2, to engage the" shoulder L which limits its movement in that direction. The element 7 has an oblong wedge shape below the head '8 thereof andis provided at its lower extremity with afbase 9 of a size and shape to fit the p erfforatioiri 3 for sliding movement therein in a manner similar to the head 8.

The adjusting element 7 is provided with" socket 11. The screw lO'is provided, a little a threaded opening centrally thereof adapt ued to receive an'ad usting screw 10 havlng below the'head thereof, with+a flange adapted to engage the shoulder 5*to' bear" Wedge downwardly for-adjustment. The adjustingelementf maybe raised orlowthereagainst' "whenoperating to force the ered byturning the screw 1 0 in one direction or another and the amount of adjustment may befaccurately set oif on the graduated head. 7 i

The adjusting element .7 is insertedin* the guide opening 3 from the bottom thereof, Figure 2. After inserting theelement 7 the'opening is c-losedby means of a plug 13 having a contour corresponding to that of the opening. The plug13 maybe fixed in place against the shoulder 6by peening over the edges of theopeni n g or other suit able means. The' "plug IScarries an adjustable -pilot '14 screw-threaded for adjust ment in :the plug 13 as shown in Figure 2. The pilot 149engages a socket 15 in the element -7 in which it slides as said element also acts as'a stop to limit the downward movement of the adjusting element .7, being The pilot 14:

The head 2 is further provided with edges beveled to correspond with the wedge faces of the adjusting element 7 as illustrated in- Figure 2. The cutters 16 are slidable in and out in thehead 2 for adjustment under the influence of the element 7 and are provided with transverse grooves 17 adapted to be engaged by set screws 18 threaded into the head 2. The grooves 17 are V-shaped andhave an angle correspondingwith" thatof the cone-points 19 of the set screws 18. The grooves 17 are somewhat off-set with respect to the centers of the 7 screws 18 as illustrated in Figure 3-. Thus when the screws are set down. into. the. grooves 17, they will bear against only the rear side of said grooves so as to force the cutters back against the shoulder 20'at the rear of the guide slot. The cutters are thus not only clamped against alterations of their positions but are seated firmly against the shoulder 20 so as to insure par-- allelism of their cutting edgesand to sup-- port the sameagainst the thrust incident to the boringoperation,

ItzWill be noted that when .the set screws 18 arelloosened the two cutters may be posi-. Y

tively and accurately adjusted outwardly by turning the screw 10 so as to move the adjustingv element ,7 downwardly with the screw. The element 7 is guided in the guide perforation 3 both by its head 8 and its base 9 so that an accurate rectilinearmovement: Wlll. be assuredr The element 7 1s, therefore, at alltimes accurately centered whereby it is insured that the cutters 16 .Wlll be equally adjusted. Such. adjustment i's then rendered permanent by tightening the set screws 18. Q

In the embodiment illustrated in. Figure.

4 the adjusting element may be provided with dove-tailed grooves 21 adapted to be engaged by corresponding dove-tailed projections on the cutterslGO so that by adjusting the element 70 up or down, the cutters wmay be projected or retracted as desired.

-In this embodiment also the setfscrews 180 may be 7 provided with cone shaped shanks 190 adapted to engage a correspondingly beveled edge of a clamping bar 22. The bar 22 is suitably recessed to receive a pair ofWoodrufi' keys 28 adapted to bear each against the rear edge of one of the cutters 160. When the set screws 180 are screwed down the action of the shanks 190.

against the beveled edge of the clamping bar 22 will force said bar to the left, Figures A and 6,- so as to force the cutters to.

- pansion.

screws may be provided with enlarged heads 25 adapted to take under the bar 22 so as to keep the screws from falling out 1 when loosened.

It will be noted that this invention providesa simple and effective device for adjusting expansible boring tools. The adjusting elements 7 and 70 being guided in the boring head are adapted to equally and simultaneously adjust the cutters for ex- The construction is simple and rugged and economical to manufacture. The

oblong shape of the wedge provides an extended bearing agalnst the inner edges of the cutters so as to insure their remaining in parallelism and to take any radial thrust incident to the cutting operation.

It is obvious that various changes may be made details of construction without departing from the spiritof this invention; it is, therefore,.to be understood that this invention isnot to be limited to the'specific details shown and, described.

Having thus described the invention, what is claimed is:

1. An expansiblelboring tool, comprising,-

a. bar having an oblong guideway therein and extending therealong, a long cutter blade guided for movement in said bar transversely of said guideway, an oblong adjusting element having an oblong head and an oblong base, each working in said guideway and having a wedgebetween said head and'base adapted to have a substantially continuous bearing against along side of said blade,'means to interconnect said wedge and blade whereby movement of said wedge will move said blade in either directhe left against the shoulder 24; at thefront of the guide 1 slot.

thecutters' regardless of anytilting of the bar 22 which may be occasioned by unequal During this operation the Woodruff keys 23 may turn in their sockets'so as to provide an even bearing against.

adjustment of the two screws180. These 

